A Texas appeals court has suspended the execution of convicted murderer Rodney Reed -- who has long claimed his innocence -- in a case that has attracted widespread public attention and a celebrity-backed campaign.

Reed, a 51-year-old African-American, was sentenced to death in 1998 after being convicted by an all-white jury of the rape and murder of Stacey Stites, a 19-year-old white woman.

His execution by lethal injection had been set for November 20, but Reed says he did not commit the crime, and his lawyers and supporters say that evidence proves he is innocent.

The Texas Board of Pardons and Paroles announced on Friday that it had ‘voted unanimously to recommend the governor grant a 120-day reprieve’ to Reed, who had appealed for clemency.

The state appeals court then halted the execution later in the evening.

Millions of people, including US lawmakers and Hollywood celebrities Kim Kardashian and Susan Sarandon, have signed petitions supporting Reed.

Kardashian said on social media she was with Reed when he received news about the reprieve.

Although traces of Reed's DNA were found in the victim, he has always maintained that he and Stites were secretly having an affair.

Reed's lawyers say that evidence obtained after the trial points to another suspect -- the victim's fiance, Jimmy Fennell, a former policeman who later served a 10-year prison sentence for another rape.

‘The strong evidence exonerating Mr Reed and implicating Fennell continues to mount,’ the lawyers wrote in the clemency petition lodged with the state's Republican governor, Greg Abbott.

In the clemency request, they included a testimonial from a former co-worker of the victim who confirmed the affair.

According to another affidavit, a former prison inmate said he heard Fennell brag during a prison yard conversation about committing the murder.

Fennell has denied involvement in Stites' murder.

The Texas board declined Reed's request to downgrade his sentence.

His lawyers also have filed a petition with the US Supreme Court, seeking a stay of execution.